We have just moved into a new 1960s house and the upstairs ring main
has been extended into the loft by drilling a hole through the wall of
the back of a socket in one of the bedrooms into the airing cupboard.

2 X 2.5mm T+E then loops round the loft and back to the socket. So..
in the back of my socket I have 4 pairs of wires attached.

This to me seems wrong. I would have added a junction box in the
airing cupboard and then run one of the existing wires to that. I
would then loop from there round the loft and back to the socket.

Can anyone confirm if the way it's been done is acceptable. I would
have thought that this setup would mean an imbalance in the current
travelling round the ring.

Cheers.